From a networking perspective, as well, it makes our ad hoc reconfigurable network more scalable if we're focused on short-burst transmissions that are, technically speaking, delay-tolerant. This means that even if you're at a huge event with tons of people using goTenna, even if a gajillion of them press "send" at the exact same femtosecond, all the messages can get through in a matter of seconds if not milliseconds.
I still believe I'm with the 25% that didn't prefer asynchronous messaging.
If you want walkie-talkies, there's another entire band dedicated to unlicensed voice calls - http://www.fcc.gov/encyclopedia/family-radio-service-frs
You could ask them to make a dual mode device. MURS for text/sms (and greater distance), and FRS for voice and picture messages (with less distance).
You could stop for a second, I guess.
Instead of a sturdy walkie-talkie
Why don't you just buy a walkie-talkie? They're cheaper, they just don't interface with your phone. But it sounds like that's what you want.